Spotted wing drosophila male under a berry. Photo: K. Demchak
We caught one female in one of our 18 traps the week of June 19, and one female in each in three traps out of 18 the week of June 26. That means that it's time for growers to be spraying with effective labeled insecticides, weekly if not more frequently, to protect susceptible berry crops from spotted wing drosophila (SWD).
Cultural methods of management that reduce numbers include:
- using exclusion netting if in tunnels
- maintaining narrow rows to reduce humidity and allow better spray penetration
- harvesting more frequently--with raspberries, every day if possible
- refrigerating harvested berries as close to 32 degrees as possible
Growers can monitor with traps, check for larvae in fruit, and watch for juice stains on the receptacles of raspberries during harvest as indications of SWD presence. Or, just assume that SWD is around, because it very likely is.
Thanks to Maria Cramer, our graduate student who is working on SWD management research, for trap deployment and monitoring.